python02
#索引str1# 正向索引 从0开始从左到右取值
# 负向索引 从-1开始从右向左取值
#stry1 = "duoceshi"
#print(stry1)d
# print(stry1) string index out of range 索引越界
# print(stry1[-9])
#切片
#===>[开始索引:结束索引:步长]
# #取值取开始索引到结束索引前一位(能取开始索引,不能取结束索引)
#没有传入步长,步长默认为1(正步长)
#str1 = "du_oceshi"
#print(str1) ==du_o
#print(str1[:6]) ==du_oce
#print(str1) ==eshi
#给你一个字符串,我要取字符串最后三位怎么取==>print(str1[-3:])
#print(str1) ==du_oceshi切片中没有索引越界
# print(str1) 没有内容
# #print(str1[:]) 取全部
#print(str1[-5:-3])==ce
#str1 = "du_oceshi"
#print(str1) 空
#print(str1)==hsec
# 进行序列反转,怎么反转一个序列
# print(str1[::-1]) ==ihseco_ud
#print(str1) ==he步长为2 跳切
#print(str1[:6:-1]) ==ih
#print(str1[:4:-2]) ==is
#print(str1[-2:-6:-1])==hsec
#print(str1[-4:-2:-1])== 无内容
#字符串
#str1 = "xiaoxiao"
#1.print(str1.capitalize())== Xiaoxiao首字符大写
#2.str2 = str1.title() == 返回一个标题化的字符串,开头大写,其余小写
# print(str2) == Xiaoxiao
#print(str1.count("h")) 0 统计具体字符出现的次数
#print("#".join(str1))x#i#a#o#x#i#a#o 分隔符连接
#print("".join(str1))
# 练习
# 把字符串str1 = "user_name" 输出成UserName
# str1 = "user_name"
# str2 = str1.title()
# list1 = str2.split("_")
# list2 = list1 + list1 print("".join(list1))
# print(list2)
#strip(ab)删除字符串开头和结尾有a或b的字符
#str1 = "duoceshiud"
#print(str1.strip("ud")) ==删除开头和结尾
#print(str1.lstrip("du")) ==开头
#print(str1.rstrip("iud")) ==结尾
#print(str1.startswith("du")) ==判断以什么开始
#print(str1.endswith("shiud"))==判断以什么结束
# file_name = input("请输入您需要上传的文件名称:")
# iffile_name.endswith(".py"):
# print("文件有效")
# else:
# print("文件无效")
#find()
#str1 = "xiaoxiao"
# print(str1.find("x")) 从左开始查,结果显示下标(索引)
# print(str1.find("a",3)) 限制范围
#print(str1.rfind("i")) 从右开始查,结果显示下标
#print(str1.replace("a","d")) 替换
#print(str1.replace("x",""))空格相当于删除
# str = "xiaozhang"
# print(str.lower())
#str1 = "XIAOzhang"
#print(str1.upper()) # XIAOZHANG 小写全部转换成大写
#str1 = "XIAOzhang123"
# print(str1.upper())
#print(str1.isdigit()) False 判断是否全是数字
#print(str1.isalpha()) # True 判断是否全是字母
# str1 = "123456"
# str2 = "abcdfesd"
# str3 = "qshfk123"
# print(str1.isalnum()) True
# print(str2.isalnum()) True
# print(str3.isalnum()) True
#istitle判断字符串中首字母是否为大写,其他是否为小写; 其他不为小写为否
#str1 = "xiaozhang"
#print(str1.istitle()) False
#str1 = "XiaoZhang"
#print(str1.istitle()) False
# str1 = "Xiaozhang"
# print(str1.istitle())True
#isupper()is开头判断字符串中的字符是否都是大写
# str1 = "XiaoZhang"
# print(str1.isupper()) False
#islower() 判断是否都是小写
# str1 = "xiaozhang"
# print(str1.islower()) True
#python中的列表
#list1 = ["dcs","xian05","123456",["xiao","zhang"]]
# print(list1) == ['dcs', 'xian05', '123456', ['xiao', 'zhang']]
# print(type(list1))
# str1 = "xian001"
# list1 = list(str1)
#print(list1) #== ['x', 'i', 'a', 'n', '0', '0', '1']
# print(type(list1)) == <class 'list'>
# str2 = str(list1)
# print(str2) == ['x', 'i', 'a', 'n', '0', '0', '1'] 列表上加了引号
# print(type(str2)) == <class 'str'>
#列表使用索引赋值
#list1 = ["dcs","xian05","123456",["xiao","zhang"]]
#print(list1) ==dcs
# list1 = "think" 更改替换
# print(list1) ==['dcs', 'think', '123456', ['xiao', 'zhang']]
# 切片赋值
# list1 = ["dcs","xian05","123456",["xiao","zhang"]]
# list1 = "yes"
# print(list1) ==['y', 'e', 's', ['xiao', 'zhang']]
#append()函数可以添加任何数据类型的数据到列表中,最末尾
# list1 = ["dcs","xian05","123456",["xiao","zhang"]]
# list1.append("ching") 添加字符串
# print(list1) == ['dcs', 'xian05', '123456', ['xiao', 'zhang'], 'ching']
# list1.append(["13234"]) 添加列表
# print(list1) ==['dcs', 'xian05', '123456', ['xiao', 'zhang'], 'ching', ['13234']]
#insert()函数,根据索引位置去添加元素到列表中
# list1 = ["dus","xiao05",10000,["xiao","zhang"]]
# list1.insert(1,"mod") ==['dus', 'mod', 'xiao05', 10000, ['xiao', 'zhang']]
# print(list1)
#extend()函数,连接两个列表,传入的值是一个可迭代的对象
# list1 = ["xian05"]
# list2 = ["dcs"]
# str1 = "dcs"
# #int1 = 1009 不能被迭代
# list1.extend(list2)#相连
# print(list1) ==['xian05', 'dcs']
#index()函数,查看列表元素的索引值 ===>列表,字符串都可以使用
# list1 = ["dcs","xian05",["xiao","xiao"]]
# print(list1.index("xian05")) ===1
# str1 = "xian05"
# print(str1.index("a")) ===2
#remove()函数,移除列表中的元素
# list1 = ["dcs","xian05",["xiao","xiao"]]
# list1.remove("dcs")
# print(list1) ==['xian05', ['xiao', 'xiao']]
#del 关键字删除
# list1 = ["dcs","dcs","xian05",10086,["xiao","zhang"]]
# del list1 # 删除列表中索引位为0的元素
# del list1 # ['xian05', 10086, ['xiao', 'zhang']]
# print(list1)
# del list1
# print(list1) # ['xian05', 10086, ['xiao', 'zhang']]
# sort()函数对列表进行排序 ==> 默认排序方向是升序排列
# 进行降序排列
# 只有当列表中的元素全部为str或者全部为int的时候才能对它进行排序
# 根据ascii编码排序的原则,数字0-9>A-Z>a-z
# list1 = ["dcs","Test","china","10086","20010"]
# list1.sort() # 对列表进行排序
# print(list1) # ['10086', '20010', 'Test', 'china', 'dcs']
# list2 =
# list2.sort()
# print(list2) #
# list2.sort(reverse=True) # reverse=True降序,reverse=False升序
# print(list2) #
# sorted()函数进行排序
# 对列表参数进行排序并且生成排序之后的新的列表
# list1 = ["dcs","Test","china","10086","20010"]
# list2 = sorted(list1) # 默认升序
# print(list2) # ['10086', '20010', 'Test', 'china', 'dcs']
# list3 = sorted(list1,reverse=True)
# print(list3) # ['dcs', 'china', 'Test', '20010', '10086']
# 你知道Python中的排序吗?用哪些方法可以进行排序?sort()和sorted()的区别
# 两个排序函数
# 相同点:2个函数都是默认升序排序
# 不同点:1.sort()是一个方法,sorted()是一个函数
#sort()排序是针对原来的列表进行排序,不会生成新的列表,sorted()把原来的列表进行排序并且生成一个新的排序之后的列表
# reverse()函数,反转函数
# 怎么反转列表,用reverse()函数
# 使用列表切片为负步长进行反转列表
# list1 = ["dcs","Test","china","10086","20010"]
# list1.reverse()
# print(list1) # ['20010', '10086', 'china', 'Test', 'dcs']
# 用切片进行反转列表
# print(list1[::-1]) # ['20010', '10086', 'china', 'Test', 'dcs']
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